Reducing Irreducible Water Saturation for CO2 Injectivity
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Solution Overview
Problem
High irreducible water saturation in underground aquifers reduces the storage capacity and permeability of carbon dioxide, leading to decreased injectivity, which is undesirable for economic feasibility in carbon capture and storage (CCS) operations.
Innovation Solution
Injecting a miscible reducing agent such as acetone, methanol, or acetic acid through a wellbore to reduce irreducible water saturation around the wellbore, allowing for improved carbon dioxide injectivity by displacing water and increasing relative permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbon dioxide is injected into an aquifer with high irreducible water saturation, then storage capacity is reduced, but injectivity is also reduced due to low relative permeability
Solution Approach 1:
A reducing agent is injected into the aquifer before carbon dioxide injection to reduce irreducible water saturation. This preliminary action modifies the reservoir properties by displacing water from pore spaces, thereby improving both storage capacity and injectivity for subsequent CO2 injection operations
Solution Approach 2:
The reducing agent changes the saturation parameters of the aquifer by reducing irreducible water saturation. This parameter change increases the available pore space and improves relative permeability, enabling both higher storage capacity and better injectivity simultaneously
2Volume of stationary object
If irreducible water saturation is high, then storage space is reduced, but permeability is also reduced
Solution Approach 1:
The reducing agent is injected in advance to reduce irreducible water saturation, thereby creating more storage space and improving permeability before the actual carbon dioxide storage operation begins
Solution Approach 2:
The reducing agent acts as an intermediary substance that mediates between the water-saturated aquifer and the carbon dioxide. It displaces water from the pore spaces, allowing both increased storage space and maintained permeability for CO2 flow
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively increases carbon dioxide saturation and relative permeability, enhancing injectivity and storage capacity in the underground gas storage layer, as demonstrated by simulations and experiments.
Implementation Method 1
injecting a miscible reducing agent such as acetone, methanol, or acetic acid through a wellbore to reduce irreducible water saturation around the wellbore, allowing for improved carbon dioxide injectivity by displacing water
Implementation Method 2
The method effectively increases carbon dioxide saturation and relative permeability, enhancing injectivity and storage capacity in the underground gas storage layer
Data Source
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AI summary
Provided is a method for improving injectivity of an underground gas storage layer. The method for the injectivity of the underground gas storage layer includes performing a process of injecting a reducing agent for reducing irreducible water saturation of the storage layer through a wellbore connected up to the underground gas storage layer composed of a water-permeable rock material and performing a process of injecting carbon dioxide into the storage layer after the reducing agent is injected. Since the carbon dioxide is injected, the reducing agent and water, which are filled into a pore of the storage layer, are discharged together to reduce the irreducible water saturation around the wellbore, thereby improving the carbon dioxide injectivity of the storage layer. The reducing agent may include a surfactant or a material that is miscible with all of the carbon dioxide and the water.